The present application relates to photovoltaic cells, and more particularly to a method of forming photovoltaic cells that include a thin film structure including an ohmic contact layer and a single crystalline semiconductor material having a surface Fermi level pinned close to a band edge (either the conduction band or the valence band).
Photovoltaic cells are capable of converting solar energy into direct current electricity using semiconductor materials that exhibit a photovoltaic effect. Power generated by such photovoltaic cells has long been seen as a clean sustainable energy technology which draws upon the sun for energy. Although the energy conversion efficiency of photovoltaic cells keeps increasing, the dollar/watt figure-of-merit is still much higher than other energy sources.
Thin film photovoltaic cells, which typically have film thicknesses from a few nanometers to tens of micrometers, have advantages of reduced cost, flexibility, portability, and offer more applications as compared to their non-thin film counterparts. However, the thin film photovoltaic approaches existing today suffer from various shortcomings including, for example, low efficiency for amorphous silicon and organic solar cells, and high toxicity and material scarcity for CdTe and CIGS based devices. As such, there exists a need for developing a low-cost single-crystal semiconductor material thin film photovoltaic technology which overcomes the shortcomings of prior art thin film photovoltaic cells.